It is known to produce planar or three-dimensional capacitors using an aluminum technology (RIE or reactive ion etching) or a copper technology (damascene method). The capacitor is conventionally obtained from an MIM (metal-insulator-metal) capacitive multilayer in which the lower layer is a conductive material, such as for example TiN, the insulator is a dielectric material having a high permittivity (or high-k material) and the upper electrode is a conductive material, such as for example TiN. Generally, these capacitors are produced individually and then assembled in a complex circuit. The production of capacitors within an integrated circuit still remains a challenge today since this production must be compatible with the existence of active components within this complex circuit.
It is known in the scientific literature that copper can fulfill the role of electrode for a high-permittivity dielectric. The use of a copper electrode has many advantages. This is because the electronic operation of copper is high. The barrier height between the electrode and the dielectric is thus favorable for limiting leakage currents. However, the use of copper as electrode has a number of disadvantages. For example, since the process steps are often carried out in an oxygen atmosphere, the copper interface has a tendency to oxidize very easily, making the material of poor quality. In addition, copper has a tendency to diffuse into the dielectric, substantially degrading the electrical performance. Finally, when the dielectric is an oxide, such as for example tantalum oxide (Ta2O5), copper has a tendency to be oxidized by oxygen from the oxide diffusing into the copper layer.